Well you can't go from not being able to solo at all, to being able to solo after some advice, so you might be out of luck for this competition, but I'll help you.

Since you want it kind of bluesy, find a minor pentatonic scale that best fits with all the chords being played under it. Those power chords you gave us are a little messy and don't fit easily into one key, but I'd use the A minor pentatonic over those.

So once you got the scale ready, the best way to make an anywhere near decent solo is to not flip out and start mindless pentatonic runs. Those are fine in short bursts, but they get tired and boring very quickly. Make sure you have a at least one repeating melody in your solo, something the listener can latch on to.

It's hard to tell you how to solo correctly, because there's not only one right way, but just be tasteful and make little melodies here and there is the best I can say.